Noncompetitive Inhibition of Enzymes Occurs

Question

Noncompetitive inhibition of enzymes occurs
A) when a cofactor, instead of a reactant, binds to the enzyme active site.
B) when a substance binds to an enzyme at a site away from the active site.
C) by blocking the production of an enzyme.
D) when a substance other than the substrate binds at the active site of an enzyme.

Accepted Answer

Noncompetitive inhibition occurs when a substance binds to an enzyme at a site away from the active site, which causes a conformational change that makes the active site less effective. This is different from competitive inhibition, which occurs when a substance competes with the substrate for binding at the active site of an enzyme. Choice A describes the binding of a cofactor, which can be essential for enzyme function but is not necessarily inhibitory. Choice C describes a different mechanism entirely, in which the production of an enzyme is blocked, rather than its activity. Choice D is a form of competitive inhibition.